Merge pull request #55 from mahinshaw/group-by

Add group-by clause for select statements.

Author: mpenet

src/clj/qbits/hayt.clj

@@ -1,6 +1,6 @@
 (ns qbits.hayt
   "This namespace contains aliases for qbits.dsl.*, qbits.fns and qbits.utils"
-  (:refer-clojure :exclude [update])
+  (:refer-clojure :exclude [update group-by])
   (:require
    [qbits.hayt.ns :as uns]
    [qbits.commons.jvm :refer [compile-if-ns-exists]]

src/clj/qbits/hayt/cql.clj

@@ -300,7 +300,7 @@
      (-> sb
          (str! "SELECT ")
          (emit-row! (assoc q :from table)
-                    [:columns :from :where :order-by :limit :allow-filtering])))
+                    [:columns :from :where :group-by :order-by :limit :allow-filtering])))
    :insert
    (fn [sb q table]
      (-> sb
@@ -546,6 +546,10 @@
    (fn [sb q b]
      (str! sb " IF" (if (not b) " NOT " " ") "EXISTS"))
 
+   :group-by
+   (fn [sb q columns]
+     (str! sb " GROUP BY " (cql-identifiers-join-comma columns)))
+
    :order-by
    (let [xform-inner (comp map-cql-identifier interpose-space)
          xform (comp (map #(transduce xform-inner string-builder %))

src/clj/qbits/hayt/dsl.clj

@@ -1,5 +1,5 @@
 (ns qbits.hayt.dsl
-  (:refer-clojure :exclude [update])
+  (:refer-clojure :exclude [update group-by])
   (:require [qbits.hayt.ns :as uns]))
 
 (doseq [module '(statement clause)]

src/clj/qbits/hayt/dsl/clause.clj

@@ -1,4 +1,5 @@
-(ns qbits.hayt.dsl.clause)
+(ns qbits.hayt.dsl.clause
+  (:refer-clojure :exclude [group-by]))
 
 (defn columns
   "Clause: takes columns identifiers
@@ -23,6 +24,11 @@ ex: (columns :foo \"bar\" :baz) "
   [n]
   {:limit n})
 
+(defn group-by
+  "Clause: expects 1 or more columns.
+  ex: (group-by col1 col2)"
+  [& columns] {:group-by columns})
+
 (defn order-by
   "Clause: takes vectors of 2 elements, where the first is the column
   identifier and the second is the ordering as keyword.

src/clj/qbits/hayt/dsl/statement.clj

@@ -8,6 +8,7 @@ Takes a table identifier and additional clause arguments:
 
 * columns (defaults to *)
 * where
+* group-by
 * order-by
 * limit
 * only-if"

test/qbits/hayt/core_test.clj

@@ -1,5 +1,5 @@
 (ns qbits.hayt.core-test
-  (:refer-clojure :exclude [update])
+  (:refer-clojure :exclude [update group-by])
   (:use clojure.test
         qbits.hayt
         qbits.hayt.codec.joda-time
@@ -41,6 +41,17 @@
            (limit 100)
            (allow-filtering true))
 
+   "SELECT * FROM foo GROUP BY bar, \"baz\";"
+   (select :foo
+           (group-by :bar "baz"))
+
+   "SELECT * FROM foo WHERE foo > 1 AND foo < 10 GROUP BY foo, \"bar\" LIMIT 10;"
+   (select :foo
+           (where [[> :foo 1]
+                   [< :foo 10]])
+           (group-by :foo "bar")
+           (limit 10))
+
    "SELECT * FROM foo ORDER BY bar desc;"
    (select :foo
            (order-by [:bar :desc]))